NOTICE OF FILING Application of Duke Energy Carolinas, LLC, for Approval of Demand-Side Management and Energy Efficiency Rider 18, Increasing Residential Rates and Non-Residential Rates Docket No. 2026-79-E Why is this Notice Important? • This Notice is for electric utility customers of Duke Energy Carolinas, LLC (the “Company”), and interested persons. • The Company filed an Application for Approval of its Demand-Side Management (“DSM”) and Energy Efficiency (“EE”) Rider for 2027 (“Rider 18”) that will increase residential rates and non-residential rates with the Public Service Commission of South Carolina (the “Commission”), and the Commission decides what rates a utility can charge. What is Duke Energy Carolinas, LLC, Asking the Commission to Approve? • The Company has requested approval to recover its costs and revenue associated with DSM and EE programs under S.C. Code Ann. § 58-37-20 and the existing DSM/EE cost recovery mechanism approved by the Commission in Order No. 2021-32 (the “Existing Mechanism”). • The Existing Mechanism is currently under review by the Commission in Docket No. 2026-57-E and could be updated by the Commission by the time that rates in this docket are in effect. Those updates could impact the rates in the Application. • Therefore, the Company has proposed two sets of rates that are both higher rates than the Company is currently recovering under its previous DSM/EE Rider 17 filing for both residential and non-residential customers. • However, the Company will implement only one set of rates. The Commission must approve any rate adjustment. What Rates are Duke Energy Carolinas, LLC Proposing? • If certain provisions of the Existing Mechanism remain in place, the Company is requesting an Order allowing the Company to recover the following revenue through the proposed Rider 18: o $61,459,230 for Residential Customers; and o $52,897,618 for Non-Residential Customers. • Approval of the following billing factors for the period of January 1, 2027 – December 31, 2027: Residential Billing Factors (Existing Mechanism Rates) ¢/kWh True-up Component for Years 2021-2025 0.1339 Prospective Component for Vintage Years 2024-2027 0.7075 Residential Rider 18 (Total) 0.8414 Non-Residential Billing Factors (Existing Mechanism Rates) ¢/kWh Year 2021 EE Participant – True up (0.0084) Year 2021 DSM Participant – True up 0.0003 Year 2022 EE Participant – True up 0.0000 Year 2022 DSM Participant – True up (0.0008) Year 2023 EE Participant – True up 0.0144 Year 2023 DSM Participant – True up 0.0029 Year 2024 EE Participant – True up 0.0112 Year 2024 DSM Participant – True up (0.0036) Year 2025 EE Participant – True up 0.2449 Year 2025 DSM Participant – True up 0.0010 Year 2024 EE Participant – Prospective 0.0273 Year 2025 EE Participant – Prospective 0.1001 Year 2026 EE Participant – Prospective 0.0664 Year 2027 EE Participant – Prospective 0.3673 Year 2027 DSM Participant – Prospective 0.1364 • If certain provisions of the Existing Mechanism are updated, the Company requests: o An Order allowing the Company to recover the following revenue through the proposed Rider 18: ▪ $60,610,165 for Residential Customers; and ▪ $53,039,158 for Non-Residential Customers. Based on the total cost to be recovered under the proposed Rider 18, as shown on Exhibit A (Common Mechanism), the billing factors applicable to South Carolina customers for the billing period January 1, 2027, through December 31, 2027, would change as follows¹ (otherwise, the Existing Mechanism Rates listed above remain unchanged): Residential Billing Factors (Common Mechanism Rates) ¢/kWh True-up Component for Years 2021-2025 0.1339 Prospective Component for Vintage Years 2024-2027 0.6959 Residential Rider 18 (Total) 0.8298 Non-Residential Billing Factors (Common Mechanism Rates) ¢/kWh Year 2027 EE Participant-Prospective 0.3678 Year 2027 DSM Participant-Prospective 0.1382 ¹ The updated system benefit values proposed under the Common Mechanism drive this calculation. The case was filed according to S.C. Code Ann. Section 58-37-20 and S.C. Code Ann. Regs. 103-819 and 103-823, and the Rules of Practice and Procedure of the Commission. For the Company’s proposal and for the entire Case visit: https://dms.psc.sc.gov/Web/Dockets/Detail/119660 Who Can I Talk to About This Notice? Duke Energy Carolinas, LLC 803-988-7132 Office of Regulatory Staff 803-737-5230 or 1-800-922-1531 Department of Consumer Affairs 803-734-4200 or 1-800-922-1594 Public Service Commission 803-896-5100 How Can I Participate in this Case? A stakeholder may participate in the case by the ways listed below. Option A: File a Letter of Protest by • Emailing the completed Letter of Protest to contact@psc.sc.gov; or • Mailing the completed Letter of Protest to 101 Executive Center Drive, Suite 100, Columbia, SC 29210. More information is available here: https://psc.sc.gov/consumer-info/file-letter-protest Option B: File a Petition to Intervene. An Intervenor becomes a party in the case. Intervenors have the right to testify, crossexamine witnesses, seek reconsideration of the Commission’s Final Decision, and must follow the Commission’s Rules of Practice and Procedure. To intervene, you must: • Email a Petition to Intervene to contact@psc.sc.gov no later than Monday, June 1, 2026; or • Mail a Petition to Intervene to 101 Executive Center Drive, Suite 100, Columbia, SC 29210 no later than Monday, June 1, 2026. Please include your email address. **You must give a copy of your Petition to Intervene to all Parties in this case. Petitions to Intervene must meet the requirements of Commission Regulation 103-825 and must be approved by the Commission. Intervenors must file written comments with the Commission regarding Duke Energy Carolinas, LLC’s Application in Docket No. 2026-79-E on or before July 1, 2026 (Order No. 2022-506). In the above referenced case, if the proposed tariffs contain any request for a change of rates, the proposed rates may be changed by the Commission. Persons seeking further information about these procedures should contact the Commission at 803-896-5100 or visit its website at www.psc.sc.gov. Monday, March 23, 2026 GRR